Recently, in card-like storage media such as credit cards, ID cards and cash cards, there has been development in, in addition to magnetic cards, IC cards mounting an IC module that contains in the card material semiconductor memory such as microprocessors, RAM (random access memory), ROM (read only memory) and the like. As this type of IC card, there are for example contact type IC cards, non-contact type IC cards, and IC cards having both functions of contact and non-contact type IC cards. Any of these IC cards is superior to other card-like storage medium in the point of having extremely large amount of information storage and having security property.
Most of these cards are formed by plastic (resin). Card information such as a personal name, and registration number and the like are stored in manufactured cards, and the card information are read out by various readers.
Various plastic cards including IC cards are manufactured by layering a plurality of card component sheets, followed by heat welding. Conventionally, the collation of card component sheets are performed mostly by hand, one by one in the order of the layering, and then point welding is performed by heat welding or ultrasonic welding. To automate layered collation and the welding of collate sheets, it is necessary to transfer a large rigidity-free resin sheet of 50 to 250 μm, perform positioning for image processing, and collate and weld one by one. Therefore there is the drawback of requiring a large-sized expensive collation facility.
In the conventional plastic cards other than IC cards, all layer sheets such as magnetic stripes, an outermost layer sheet and design pattern are collated, and a layered card is formed in a single press step. In the case of IC cards, however, a convex-like antenna copper pattern and a convex-like IC chip are contained in the vicinity of the center of card component sheets. In manufacturing this IC card, if individual card component sheets are layered and heat-pressed, as has been conventional, the layer sheets follow the shape of the convex-like IC chip of an inner layer during the heat press. As a result, the print pattern in the vicinity of the IC chip is remarkably disturbed and deformed, thereby causing the fatal drawback in appearance quality.
For example, as one type of IC cards, there is a rewrite IC card having in the surface thereof a leuco printing layer for writing information. In this card, the distortion of the card surface in the vicinity of the IC chip may cause the fatal drawbacks on the leuco printing layer, such as character blur and missing of print character in write information, because a uniform gap with a thermal head for writing information is not assured.
Referring to FIG. 38, the layered structure of a conventional IC card will be described.
As shown in FIG. 38, the conventional IC card is constructed around an antenna substrate 1 serving as the core of the layered structure.
An anisotropic conductive film 2 having adhesive property is attached to a position where an IC chip is layered the upper surface of the antenna substrate 1. Subsequently, a non-contact type IC chip 3 is stuck to the upper surface of the anisotropic conductive film 2, for example, at a surface pressure of 800 g, while heating at 180 to 250° C. At this time, one of three bumps of the non-contact type IC chip 3 makes contact with the anisotropic conductive film 2 and forms a circuit on the surface of an antenna pattern. Other bumps penetrate the anisotropy conductive film 2 and form a circuit with an antenna pattern provided on the rear surface of the antenna substrate 1. Then, in order to assure the continuity property of the IC chip 3 that is an important part, the upper surface of the IC chip 3 is sealed with, for example, an adhesive material 4a to which an epoxy adhesive containing 10% filler is applied. Further, in order to protect the sealed IC chip 3, reinforcing protection is performed by disposing a reinforcing plate 5a made of stainless steel or the like on the upper surface of the adhesive 4a. An adhesive 4b and a reinforcing plate 5b made of stainless steel or the like are layered on the rear surface of the antenna substrate 1, thereby completing the layering of the antenna substrate 1.
Adhesive sheets 6a and 6b are respectively layered on the upper and lower surfaces of the antenna substrate 1 after the completion of the layering, and an upper armoring material 7a and the lower armoring material 7b are stuck to the adhesive sheets 6a and 6b, respectively. A recess portion 6c that serves as clearance for an IC chip is formed in the adhesive sheets 6a and 6b. 
Magnetic stripe shielding layers 7c and 7d are layered via a magnetic stripe 7e on the upper surface and the lower surface of the upper armoring material 7a and lower armoring material 7b, respectively. Further, printing ink layers 8a and 8b are layered on the upper surface of the upper magnetic stripe shielding layer 7c and on the lower surface of the lower magnetic stripe shielding layer 7d, respectively (in the case of the rewrite card, the outermost layer is the leuco printing layer, and the magnetic stripe shielding layer is removed).
To the above-mentioned layered structure, respective card component sheets are stuck under thermal press of, for example, 100 to 200° C. and approximately one ton per card, thereby forming the card. Since in the layering by heat press the layer materials stretch somewhat due to the thermal press, the card is formed by contour punching using an IC chip as a reference.
Although FIG. 38 gives explanation in terms of single leaf size (one card), a heat-press-layer-bonding is performed for a large size (approximately A3 size) of multi-leaves size (18 cards) in layer bonding of layers in a general heat-press.
In the manufacture of the IC card so constructed, a large-sized vacuum multistage press has conventionally been used. In vacuum multistage press system, card component sheets in which an antenna substrate mounting an IC chip and an armoring material are collated in the order of layer bonding are charged to a press platen disposed within a large vacuum chamber. After the inside of the vacuum chamber is subjected to vacuum pumping up to a predetermined pressure, layered a plurality of IC cards are manufactured at a time through respective processing of preheat press processing, heat press processing and cooling press processing.
The vacuum multistage press system requires much time for one cycle from degassing in the inside of the vacuum chamber to raising temperature and cooling of the press platen. Therefore, 6 sets to 12 sets of card component sheets, in which multi-leaves size (approximately A3 size) corresponding to 18 cards is collated and layered, are charged in the inside of the vacuum chamber at a time, thereby increasing the amount of charge to maintain productivity.
However, in the above-mentioned vacuum multistage press system, having the press platen in the vacuum chamber serve heating function and cooling function, respective steps of preheating, heating and cooling are performed continuously. However, manufacture cycle time up to the completion of layer bonding of card component sheets is long, and therefore there are difficulties in maintaining productivity and mass production capability. Further, there is also a problem that along with rapid heating and rapid cooling of the press platen, energy consumption becomes tremendous, thus being poor in economics.
To eliminate the above problem, Japanese Patent Unexamined publication No. 2000-182014 describes a plate for heat press 80 wherein a pair of upper and lower plate members 81a and 81b press a plurality of collated and layered card component sheets C, and a degassing hose 84 connecting to a degassing unit 83 is connected to a circular hollow ring member 82 disposed in the outer peripheral portion of a pressing surface thereof, as shown in FIG. 39.
The plate for heat press 80 has a structure such that an upper plate member 81a is overlaid via a sealing member 85 on a lower plate member 81b fixed to respective edge portions of a cruciform arm member 90. As shown in FIG. 40, there is constructed such that by partial rotation drive, 90° each, of the arm member 90, respective plates for heat press 80 are positioned sequentially at a preheat press portion 86, a heat press portion 87, a cooling press portion 88, and a standby portion 89 where there is performed supply and discharge of card component sheets by a transfer mechanism 91.
With this construction, only degassing processing between the upper and lower plate members 81a and 81b having a low spatial volume is required, and therefore a desired degree of vacuum is obtainable in a short time. Additionally, it is arranged such that the plate for heat press 80 is transferred sequentially to the respective press portions 86 to 88, which are maintained at their respective predetermined temperatures. Therefore, as compared to the conventional vacuum multistage press system, card manufacturing cycle time is reduced, so that productivity and mass production capability can be improved, and at the same time energy-saving capability is also improved.
In the meantime, in the layer bonding of various sheets of the IC card having the construction shown in FIG. 38, a lateral force is exerted during layering or heat press, and therefore a lateral dislocation occurs between adjacent sheets in a plurality of card component sheets, failing to perform accurate collation in some cases. Conventionally, in order to eliminate this drawback, two or more reference holes passing through all card component sheets are formed in margin portions in the card component sheets, which do not finally construct an IC card and the like, and heat press is performed while securing the positional relationship between the respective card component sheets by positioning pins passing through and blocking at least two of the aforesaid reference holes, thereby preventing the above-mentioned character blur and print drift (for example, Japanese Patent Unexamined Publication No. 2000-33791).
However, mutual fixing of the plurality of card component sheets with use of these positioning pins suffers from a problem that, if two positions of disposing the positioning pins are improper, the card component sheets cause distortion and twisting, and if heat press is performed in this state, print drift or the like occurs so that not only the appearance deteriorates but also the mechanical strength of the card degrades due to residual stress.
On the other hand, in the construction of the plate for heat press 80 described in Japanese Patent Unexamined Publication No. 2000-182014, the collation of the card component sheets C to be layered on the plate member 81b exclusively depends upon the repeat accuracy of sheet supply position available from the transfer mechanism 91, and it is therefore difficult to obtain high collation accuracy. In general, as the sheet size increases, the collating operation between sheets becomes more difficult, and high collation accuracy is also required.
In addition, since in the conventional plate for heat press 80, the hollow circular ring member 82 is constructed as a degassing path, it is necessary to ensure the escape of residual air due to deformation by reducing the board thickness of the pressing surfaces of the plate members 81a and 81b to about 1 mm. Hence, when trying to from high vacuum, the deformation of the aforesaid pressing surfaces becomes significant, thus failing to perform accurate heat press operation. There is also a possibility that collation accuracy is disturbed due to the deformation of the pressing surface.
Further, there is a problem that in order to maintain the vacuum pressure of the inside of the plate for heat press 80, it is necessary to have the degassing hose 84 follow along with the transfer of the aforesaid plate 80, and therefore one is forced to accept limitations as to the degree of freedom of apparatus design.
Additionally, when noted in the viewpoint of a card manufacturing apparatus, the respective press sections 86 to 88 for preheating, heating and cooling are respectively arranged individually in a cluster. Accordingly, to additions of the press sections such as to form the preheating press section in multi-stage, it fails to take a rapid measure, thereby making it very difficult to accurately manufacture a vast variety of plastic cards in accordance with the combination of card substrate component materials.
Additionally, since the transfer path of the plate for heat press 80 is planar, it is impossible that a plurality of paired heating/cooling press portions are disposed so as to manufacture many types of plastic cards in a single apparatus. That is, this results in a construction far apart from a card manufacturing apparatus covering a vast variety of types required in the present manufacturing field, which is small size and inexpensive and has introduction effect.
The present invention is made taking the above-mentioned problems into consideration, and an object thereof is to provide a plastic card and a plastic card manufacturing method which can prevent the occurrence of distortion and twisting when manufacturing a plastic card by welding card component sheets by heat press, while securing their mutual positional relationship with use of a plurality of positioning pins.
Further, another object of the present invention is to provide a plate for heat press which can maintain vacuum of the inside a plastic card to be manufactured in such a way that the plastic card is separated from a degassing unit while preventing the distortion and twisting of the plastic card to be manufactured.
Further, another object of the present invention is to provide a card manufacturing apparatus which can properly manufacture various plastic cards by flexibly responding to changes in the layout of a press section and to additions of the press section, and which can manufacture many types of plastic cards in a single apparatus.